Zeolite-based materials for the selective catalytic reduction of NOx with hydrocarbons

Traa, Yvonne; Burger, Benjamin; Weitkamp, Jens

doi:10.1016/s1387-1811(99)00030-x

Cited by 346 publications

(222 citation statements)

References 186 publications

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“…The highest emission of total PAHs from Veh3-DPF3 could be attributed to its less efficient control of the gas-phase PAHs. During idle operation, the temperatures of the exhaust were too low ($100 C) (Table S.6, Supplemental Materials) to activate the catalyst (van Setten et al, 2001;Herner et al, 2009) and hence a negligible effect was expected from the DOC in reducing gas-phase PAHs via oxidation. Veh1-DPF1þSCR2 was the lowest emitter of gas-phase PAHs during cruise (0.001 mg/mile) and UDDS (0.06 mg/mile) cycles among all vehicles with aftertreatment.…”

Section: Resultsmentioning

confidence: 99%

“…Veh1-DPF1þSCR2 was the lowest emitter of gas-phase PAHs during cruise (0.001 mg/mile) and UDDS (0.06 mg/mile) cycles among all vehicles with aftertreatment. The SCR2 was a zeolite-based SCR and zeolite could absorb a portion of the gaseous pollutants (Traa et al, 1999). However, a more systematic study should be conducted to further investigate the impact that a catalyst has on the reduction of gas-and particle-phase PAHs and the impact that different catalysts have.…”

Section: Resultsmentioning

confidence: 99%

“…Diesel particle filters (DPF) and selective catalytic reduction (SCR) are technologies developed to allow meeting the 2007 PM and 2010 NO X standards, respectively (Burtscher, 2005;Maricq, 2007). A diesel oxidation catalyst (DOC) is often added as a part of a DPF system to control the gaseous pollutants, such as hydrocarbons (HC) and carbon monoxide (CO) (van Setten et al, 2001), and also to generate NO 2 , which helps with regeneration (Cooper and Thoss, 1989). The after-treatment effectively reduces PM and NO X emissions from diesel exhaust, but also changes the physical and chemical properties of the diesel exhaust and even its toxicity (Burtscher, 2005;Maricq, 2007;Biswas et al, 2009a;Herner et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Emissions of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs from heavy-duty diesel vehicles with DPF and SCR

Herner

Robertson

et al. 2013

Journal of the Air & Waste Management Association

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In total, 24 polycyclic aromatic hydrocarbons (PAHs) in both gas and particle phases and 35 nitro-PAHs in particle phase were analyzed in the exhaust from heavy-duty diesel vehicles equipped with after-treatment for particulate matter (PM) and NO X control. The test vehicles were carried out using a chassis dynamometer under highway cruise, transient Urban Dynamometer Driving Schedule (UDDS), and idle operation. The after-treatment efficiently abated more than 90% of the total PAHs. Indeed, the particlebound PAHs were reduced by >99%, and the gaseous PAHs were removed at various extents depending on the type of after-treatment and the test cycles. The PAHs in gas phase dominated the total PAH (gas þ particle phases) emissions for all the test vehicles and for all cycles; that is, 99% of the two-ring and 98% of the three-ring and 97% of the four-ring and 95% of the carcinogenic PAHs were in the gas-phase after a diesel particle filter (DPF) and not bound to the very small amount of particulate matter left after a DPF. Consequently, an evaluation of the toxicity of DPF exhaust must include this volatile fraction and cannot be based on the particle fraction only. The selective catalytic reduction (SCR) did not appear to promote nitration of the PAHs in general, although there might be some selective nitration of phenanthrene. Importantly the after-treatmtent reduced the equivalent B[a]P (B[a]Peq) emissions by >95%, suggesting a substantial health benefit.Implications: This study demonstrated that after-treatments, including diesel particulate filters (DPF), diesel oxidation catalysts (DOC), and selective catalytic reduction (SCR), significantly reduce the emissions of PAHs from heavy-duty diesel engines. The gasphase PAHs dominate the total PAH (gas þ particle phases) emissions from heavy-duty diesel vehicles retrofitted with various DPFs and not bound to the very small amount of particulate matter left after a DPF. Consequently, an evaluation of the toxicity of DPF exhaust must also include this volatile fraction and cannot be based on the particle fraction only.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Emissions of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs from heavy-duty diesel vehicles with DPF and SCR

Herner

Robertson

et al. 2013

Journal of the Air & Waste Management Association

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“…Many efforts have been carried out to develop alternative catalysts for NOx reduction in excess oxygen [6,7,5,[8][9][10]. Ir-based catalysts have been reported be good catalysts for NOx reduction and received much attention from both experimental [11][12][13][14][15] and theoretical [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Ir/ZSM-5/cordierite monolith for catalytic NOx reduction from automobile exhaust

Zhang

Guan

2008

Catalysis Communications

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Ir/ZSM-5/cordierite was studied as promising catalyst for the reduction of nitrogen oxides from automobile exhaust under both stoichiometric combustion and lean conditions. ZSM-5 was in situ synthesized on the surface of honeycomb cordierite substrate and iridium was introduced to ZSM-5/cordierite by wet impregnation. Under stoichiometric combustion, Ir/ZSM-5/cordierite exhibited good catalytic activity approaching commercial three-way catalysts, and the three main pollutants nitrogen oxides, carbon monoxide and unburned hydrocarbons could be purified simultaneously. Under lean conditions, Ir/ZSM-5/cordierite also exhibited quite good deNOx activities though excess oxygen showed inhibition effect on NOx reduction.

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“…De este modo los resultados obtenidos con el catalizador basado en óxidos mixtos Sn-Cu-Al son muy interesantes, mostrando alta actividad en los primeros minutos de reacción en presencia de 1.5% de oxígeno, pero siendo desactivado a medida que avanza la reacción. La importancia del Sn como metal activo para este tipo de reacción es conocida [85][86][87][88][89][90] . 2930313233 De esta manera se cree que la mejora del comportamiento catalítico del sistema podría explicarse por un doble efecto de los metales incorporados: en primer lugar, el efecto sinérgico entre los iones de cerio y cobre y en segundo lugar, la existencia de una fuerte El CeO 2 precipitado presenta actividad catalítica en ausencia de oxígeno en la alimentación y se desactiva completamente en presencia de pequeñas cantidades de oxígeno.…”

Section: Efecto De Las Condiciones De Activación Y Del Contenido De Cunclassified

Reducción catalítica de Óxidos de Nitrógeno (NOx) en corrientes gaseosas

Paredes¹

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Reducción catalítica de Óxidos de Nitrógeno en corrientes gaseosas Agradecimientos ________________________________________________________________ ______________________________________________________________________ AGRADECIMIENTOSA Dios todopoderoso, por estar conmigo en cada paso que doy, por fortalecer mi corazón e iluminar mi mente y por haber puesto en mi camino a aquellas personas que han sido mi soporte y compañía durante el desarrollo del presente trabajo.A mis tutores, Drs. Freddy E. Imbert y A. Eduardo Palomares G., por el apoyo que me brindaron en todas las etapas de investigación, análisis y elaboración del presente trabajo, permitiéndome generosamente utilizar el gran caudal de su conocimiento sobre la materia y su enorme experiencia, para poder desarrollar esta tesis.A los miembros del Jurado por su colaboración desinteresada y oportuna, aportando sugerencias valiosas en el desarrollo de este trabajo.

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Zeolite-based materials for the selective catalytic reduction of NOx with hydrocarbons

Cited by 346 publications

References 186 publications

Emissions of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs from heavy-duty diesel vehicles with DPF and SCR

Emissions of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs from heavy-duty diesel vehicles with DPF and SCR

Ir/ZSM-5/cordierite monolith for catalytic NOx reduction from automobile exhaust

Reducción catalítica de Óxidos de Nitrógeno (NOx) en corrientes gaseosas

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